System for determining force imparted by a filter in a variable flow environment and related methods of use

ABSTRACT

A control system for a variable flow filtration system that is configured for receiving an operating condition of a variable speed impeller of the variable flow filtration system; determining a threshold filter force associated with the received operating condition to determine an increased threshold filter force proportionally to increases in the received operating condition; receiving one or more real-time environmental conditions of the variable flow filtration system; modifying the determined threshold filter force based on the received one or more real-time environmental conditions; receiving a real-time filter force imparted by a filter of the variable flow filtration system on a load cell or other filtration system component, the filter force being imparted by a flow of gas or fluid driven by the variable speed impeller; comparing the received real-time filter force to the modified determined threshold filter force; and generating a filter status notification based on the comparison.

RELATED APPLICATIONS

This application claims priority to U.S. Provisional Application No.61/975,463 filed Apr. 4, 2014, the entire disclosure of which is herebyincorporated herein by reference in its entirety.

TECHNICAL FIELD

Various embodiments of the present disclosure relate generally to afiltration system. More specifically, exemplary embodiments of thepresent disclosure relate to filter systems and methods for determininga loading condition of a filter in a variable flow environment.

BACKGROUND

Filtration is a ubiquitous technique used for removing particulates andother unwanted matter from any type of fluid or gas. For example, inmany heating, ventilation and air conditioning (HVAC) systems, air (andother fluids and gasses) are filtered to remove debris within anenclosed space of a temperature-controlled environment. In the case ofHVAC systems, for example, as the air is circulated, an air filtercollects and traps particulate matter which is later removed via eitherfilter replacement or cleaning. A dirty or loaded air filter places astrain on the air movers of the HVAC system, which can cause increasedpower consumption, reduced airflow, mechanical stress on the motors ofthe air movers, and shorter system life expectancy. In some instances,air filters are physically inspected to determine if maintenance orreplacement is necessary. In other instances, air filters are replacedat scheduled intervals, even if the air filter does not necessarily needto be changed. Often, air filter replacement and/or cleaning does nottake place at proper intervals, and overall system performance isnegatively impacted.

Likewise, liquid and gas filtering systems are an integral component inthe gas and oil industry, and in other systems that involve the removalof contaminants from a flowing stream of liquids and gases. For example,in automotive and industrial applications, fluid filters are used toremove particulates from motor oils (e.g., using an oil filter),refrigerants, coolants, and brake fluids. In the case of industrialapplications, many companies spend significant time and resources onmonitoring, scheduling, and replacing dirty oil and coolant filters, andon repairing damage that occurs from overly dirty fluid filters.

Moreover, the nature of filtration is changing due to the changingnature of forced fluids and air systems. In particular, whereas in thepast, air and fluids were either being driven, or not, in modernsystems, air and fluids are more often being driven at variable speedsand forces. As a result, existing techniques are insufficient fordetermining filter loading by measuring an amount or extent of cloggingor dirtiness.

Accordingly, a need exists for a system to accurately determine thestatus of filters by determining an amount or extent of clogging ordirtiness of fluid/air filters in a variable flow environment.

SUMMARY OF THE DISCLOSURE

According to certain embodiments, systems and methods are disclosed fordetermining force acting on a filter and related methods of use.

In one aspect, the present disclosure is directed to a filter system.The filter system may include a housing, and a filter media supported bythe housing. The filter system may also include a sensor coupled to thefilter media to measure a force exerted by the filter media.

Various examples of the present disclosure may include one or more ofthe following features: wherein the sensor may be mounted at adownstream surface of the filter media; wherein the sensor may beconfigured to measure a compressive force exerted by the media; whereinthe sensor may be mounted at an upstream surface of the filter media;wherein the sensor may be configured to measure a tensile force exertedby the filter media; wherein sensor may be configured to measure two ormore forces exerted by the filter media in different directions; furtherincluding a receiver that may be in communication with the sensor;wherein the sensor may communicate a loading condition of the filter tothe receiver.

In another aspect, the present disclosure may be directed to a filterfor use with an HVAC system. The filter may include a housing disposedwith a duct of the HVAC system, and a filter media supported by thehousing. The filter may also include a sensor coupled to the filtermedia to measure a force exerted by the filter media, and a receiver incommunication with the sensor. The sensor may be configured tocommunicate the measured force to the receiver, and the measured forcemay be indicative of a loading condition of the filter media.

In one aspect, the present disclosure is directed to acomputer-implemented method of generating a filter status notificationor signal of a filter in a variable flow environment, thecomputer-implemented method comprising: receiving an operating conditionincluding one or more of a fan setting, a pump setting, an intensitysetting, a fan speed, a rotational velocity, a voltage, a current, anair/fluid flow rate, and a force associated with a variable speedimpeller of a filtration system; determining a threshold filter forceassociated with the received operating condition to determine anincreased threshold filter force proportionally to increases in one ormore of the fan setting, the pump setting, the intensity setting, thefan speed, the rotational velocity, the voltage, the current, theair/fluid flow rate, and the force associated with the variable speedimpeller of the filtration system; receiving one or more real-timeenvironmental conditions including one or more of a temperaturemeasurement, a humidity measurement, an air or fluid densitymeasurement, an altitude measurement, and an air or fluid pressuremeasurement of the filtration system; modifying the determined thresholdfilter force based on the received one or more real-time environmentalconditions (i) to decrease the determined threshold filter forceproportionally to increases in the temperature measurement and/orproportionally to increases in the altitude measurement; and (ii) toincrease the determined threshold filter force proportionally toincreases in the humidity measurement, to increases in the air or fluiddensity measurement, and/or to increases in the air or fluid pressuremeasurement of the filtration system; receiving, from a load cell, areal-time filter force imparted by a filter of the filtration system onthe load cell and/or a component of the filtration system, the force ofthe filter on the component being imparted by a flow of gas or fluiddriven by the variable speed impeller; comparing the received real-timefilter force to the modified determined threshold filter force; andgenerating a filter status notification or signal based on thecomparison of the real-time filter force to the determined thresholdfilter force.

In one aspect, the present disclosure is directed to a control systemfor a variable flow filtration system, the control system comprising: adigital data storage device storing instructions for generating a filterstatus notification or signal; and a processor configured to execute thestored instructions to perform a method comprising: receiving, from avariable speed impeller of the variable flow filtration system, anoperating condition of the variable speed impeller of the filtrationsystem; determining a threshold filter force associated with thereceived operating condition to determine an increased threshold filterforce proportionally to increases in the received operating condition;receiving one or more real-time environmental conditions of the variableflow filtration system; modifying the determined threshold filter forcebased on the received one or more real-time environmental conditions;receiving, from a load cell, a real-time filter force imparted by afilter of the variable flow filtration system on the load cell or on acomponent of the variable flow filtration system, the force of thefilter being imparted by a flow of gas or fluid driven by the variablespeed impeller; comparing the received real-time filter force to themodified determined threshold filter force; and generating a filterstatus notification or signal based on the comparison of the real-timefilter force to the determined threshold filter force.

In one aspect, the present disclosure is directed to a variable flowfiltration system comprising a filter disposed across a flow of fluid orgas; a load cell disposed between the filter and a component of thevariable flow filtration system; a variable speed impeller configured todrive fluid or gas through the filter of the variable flow filtrationsystem; and a controller. The controller is configured to: receive, fromthe variable speed impeller of the variable flow filtration system, anoperating condition of the variable speed impeller of the filtrationsystem; determine a threshold filter force associated with the receivedoperating condition to determine an increased threshold filter forceproportionally to increases in the received operating condition; receiveone or more real-time environmental conditions of the variable flowfiltration system; modify the determined threshold filter force based onthe received one or more real-time environmental conditions; receive,from the load cell, a real-time filter force imparted by the filter ofthe variable flow filtration system on the load cell or the component ofthe variable flow filtration system; compare the received real-timefilter force to the modified determined threshold filter force; andgenerate a filter status notification or signal based on the comparisonof the real-time filter force to the determined threshold filter force.

Various examples of the present disclosure may include one or more ofthe following features: wherein the operating condition is received fromthe variable speed impeller of the filtration system; wherein thereal-time environmental condition is received from a sensor positionedin the filtration system; wherein the received operating condition isreceived continuously in real-time, the one or more real-timeenvironmental conditions are received continuously in real-time, and thereal-time filter force is received from the load cell continuously inreal-time; wherein the received operating condition is received at afirst predetermined interval, the one or more real-time environmentalconditions are received at a second predetermined interval, and thereal-time filter force is received from the load cell at a thirdpredetermined interval, wherein the first, second, and thirdpredetermined intervals are different from each other or the same;wherein the one or more operating conditions includes one or more of: afan setting, a pump setting, an intensity setting, a fan speed, arotational velocity, a voltage, a current, an air/fluid flow rate, and aforce associated with the variable speed impeller of the filtrationsystem; wherein the one or more environmental conditions include one ormore of: a temperature measurement, a humidity measurement, an air orfluid density measurement, an altitude measurement, and an air or fluidpressure measurement of the filtration system; wherein modifying thedetermined threshold filter force based on the received one or morereal-time environmental conditions comprises (i) decreasing thedetermined threshold filter force proportionally to increases in thetemperature measurement and/or proportionally to increases in thealtitude measurement; and (ii) increasing the determined thresholdfilter force proportionally to increases in the humidity measurement, toincreases in the air or fluid density measurement, and/or to increasesin the air or fluid pressure measurement of the filtration system;wherein the load cell is mounted at an upstream or downstream surface ofthe filter; wherein the load cell is configured to measure a compressiveor tensile force exerted by the filter.

Additional objects and advantages of the disclosed embodiments will beset forth in part in the description that follows, and in part will beapparent from the description, or may be learned by practice of thedisclosed embodiments. The objects and advantages of the disclosedembodiments will be realized and attained by means of the elements andcombinations particularly pointed out in the appended claims.

It is to be understood that both the foregoing general description andthe following detailed description are exemplary and explanatory onlyand are not restrictive of the disclosed embodiments, as claimed.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are incorporated in and constitute apart of this specification, illustrate various exemplary embodiments andtogether with the description, serve to explain the principles of thedisclosed embodiments.

FIG. 1A is a perspective view of an exemplary industrial HVAC system andenvironment in which embodiments of the present disclosure may bepracticed;

FIG. 1B is a perspective view of an exemplary residential HVAC systemand environment in which embodiments of the present disclosure may bepracticed;

FIG. 1C is a schematic diagram of an exemplary air flow filtrationsystem and environment in which embodiments of the present disclosuremay be practiced;

FIG. 1D is a schematic diagram of an exemplary fluid flow filtrationsystem and environment in which embodiments of the present disclosuremay be practiced;

FIG. 2A is a front view illustration of a filter system, according to anexemplary embodiment of the present disclosure;

FIGS. 2B and 2C are side view illustrations of the filter system of FIG.2A;

FIG. 3 is a side view illustration of another filter system, accordingto an exemplary embodiment of the present disclosure;

FIGS. 4A-4B are side view illustrations of another filter system,according to an exemplary embodiment of the present disclosure;

FIGS. 5A-5D are side view illustrations of another filter system,according to an exemplary embodiment of the present disclosure;

FIG. 6 is a side view illustration of another filter system, accordingto an exemplary embodiment of the present disclosure;

FIG. 7 is a front view illustration of another filter system, accordingto an exemplary embodiment of the present disclosure;

FIG. 8 is a side view illustration of another filter system, accordingto an exemplary embodiment of the present disclosure;

FIG. 9 is a flowchart of an exemplary method of generating a filterstatus notification or signal in a variable flow filtration system,according to an exemplary embodiment of the present disclosure; and

FIG. 10 is a flowchart of another exemplary method of generating afilter status notification or signal in a variable flow filtrationsystem, according to an exemplary embodiment of the present disclosure.

DESCRIPTION OF THE EMBODIMENTS

Reference will now be made in detail to the exemplary embodiments of thedisclosure, examples of which are illustrated in the accompanyingdrawings. Wherever possible, the same reference numbers will be usedthroughout the drawings to refer to the same or like parts.

In general, the present disclosure is directed to systems and methodsfor determining when a filter of an air or gas/fluid filtration systemis dirty and should be changed or cleaned. The present disclosure isapplicable to any type of filtration system, including but not limitedto HVAC systems, fluid filtering systems, water filtration, oilfiltration, or any other application in which a filter is used tocapture particulate matter from a flow of air and/or fluid. By way ofexample, FIG. 1A is a perspective view of an exemplary industrial HVACsystem and environment in which embodiments of the present disclosuremay be practiced. FIG. 1B is a perspective view of an exemplaryresidential HVAC system and environment in which embodiments of thepresent disclosure may be practiced. It should be appreciated that thesystems of FIGS. 1A and 1B are merely illustrative in nature, and arenot limiting of the present disclosure.

At a high level, the present disclosure describes a system comprising aload sensor positioned in relation to any type of filter, the loadsensor being configured to detect and measure an amount or extent ofloading or force of the filter on the load sensor and/or on a member orframe proximate to the filter. The load sensor may be any type oftransducer configured to create an electrical signal in proportion to aforce being measured. By way of example, the load sensor may be ahydraulic load cell or one utilizing hydraulic forces, a pneumatic loadcell or one utilizing compressive gaseous forces, a piezoelectric loadcell, and/or a strain gauge load cell, pressure sensitive thin filmembodiments (such as those used in touch screen applications), laserdisplacement force measurement devices, and/or linear and non-lineardisplacement force measurement devices

In one embodiment, the load cell may be configured to transmit theamount or extent of loading or force for purposes of a comparisonagainst a variable baseline level of force of the filter, by which theload cell may detect loading and/or force even in cases where the filtermedia may not necessarily deform at all, or even in cases where thefilter media deforms by a relatively small or undetectable amount. Forexample, whereas in traditional filtration applications a filter may beunder a relatively binary distribution of forces (i.e., the blower orpump is either on or off), the filter of the present disclosure may bepositioned within a variable speed air or fluid/gas environment. Forexample, the filtration system consistent with the present disclosuremay include a fan, blower, pump, or any other impeller configured tomove air, fluid, and/or gas at selectively variable speeds. In oneembodiment, the fan, blower, pump, etc. of the present disclosure may bepositioned in communication with a variable speed drive. For example,the fan, blower, pump, etc. may be disposed in communication with, andindeed driven by, any desired type of variable-frequency drive (VFD),adjustable-frequency drive (AFD), variable-speed drive (VSD), AD drive,micro drive, inverter drive, or any other type of electro-mechanicaldrive means that controls a motor speed by varying input frequency,current, and/or voltage.

In one embodiment, the variable speed drive and the load sensor may beprovided in communication with a controller that is configured toperform a method of determining an amount or extent of filter loading orclogging. For example, in one embodiment, the controller may beconfigured to receive a value of operation of a fan or blower of avariable speed filtration (e.g., HVAC or fluid) system. The value ofoperation of the fan or blower may include one or more of a fan setting,a pump setting, an intensity setting, a fan speed, a rotationalvelocity, a voltage, a current, an air/fluid flow rate, or a forceassociated with the fan or blower. Moreover, the value of operation ofthe fan or blower may include and/or be supplemented by a temperaturemeasurement, a humidity measurement, an air or fluid densitymeasurement, an altitude measurement, an air or fluid pressuremeasurement. Moreover, the value of operation of the fan or blower mayinclude and/or be supplemented by measurements or parameters associatedwith changes in height, location, and/or temperature of one or morecomponents of the filtration system. The controller may further beconfigured to receive, from the load sensor, a value of force of afilter of the filtration system against the load sensor or anothermember of the filtration system. The controller may further beconfigured to compare the received value of force of the filter toeither the received value of operation of the fan or blower, or apredetermined value of force stored in relation to the value ofoperation of the fan or blower. Finally, the controller may beconfigured to determine whether to generate a signal associated with thefilter being more loaded, clogged, or dirty, than desired. In oneembodiment, the controller may generate a signal associated with thefilter being more loaded, clogged, or dirty, than desired, if thereceived value of force of the filter is outside a threshold value(i.e., below a lower threshold or above an upper threshold) from thereceived value of operation of the fan or blower, or the predeterminedvalue of force stored in relation to the value of operation of the fanor blower.

It should be appreciated that the arrangement of the load sensor and thefilter in communication with the controller may enable detection ofincreased force even in cases when the filter is not deformed, which maybe especially advantageous in scenarios in which filter deformation isespecially undesirable. In other words, the presently disclosed systemsand methods may involve triggering a signal indicative of filterclogging at a threshold prior to deformation occurring. As describedabove, the threshold may be dependent on the type of filter media beingused. For example, high efficiency filters (often referred to as HEPAfilters), which are used to remove the smallest of particulate sizes,exert a greater force in the direction of flow, whereas other filtermedia designed to capture the larger particulate matter may have a muchgreater free area ratio. Thus, the presently disclosed arrangement mayenable setting a threshold depending on the type of filter media,whether dense to capture small particulate, or very porous, for use indirect correlation to the speed of the flow. For example, if an HVACsystem with a HEPA filter involves high volume flow at one point intime, then the force exerted by the filter may be much greater incomparison to a point in time where the required flow rate is muchlower. With a known relationship between the free area of the filter,and its inherent ability to restrict flow, and the speed of the airmover, for example, the system may determine a threshold for triggeringan indication of filter clogging. With the type of media entered intothe controller, in addition to or in alternative to its free area ratio,the controller which receives the output of the force applied by thefilter media may determine the appropriate threshold for triggering analarm, thereby preventing artificial false triggers. For example, if athreshold is set with the flow at ¾ capacity, then a false trigger mayoccur at high flow due to the inherent higher forces exerted at higherspeeds. Additionally, any changes in humidity or density would alsoimpact the forces exerted on the filter. The controller therefore may beconfigured to gather several environmental conditions to more accuratelydetermine the appropriate threshold.

In one embodiment, for example, if a VFD-driven fan is operating at, forexample, 1025 RPM, to drive 78 degree Fahrenheit air into an environmentat 72 degrees Fahrenheit, then the tolerable range of filter forcesshould be 145-155 PSI. If the force of the filter is outside the 145-155PSI range while the fan is operating within 5-10% of 1025 RPM, then analarm may be triggered. In some embodiment, a matrix, curve,mapping/map, or look-up table of tolerable forces may be generated andaccessed all possible operating conditions and/or environmentalconditions of the VFD-driven fan.

It should be appreciated that the presently disclosed systems andmethods are advantageously improved over existing systems that areapplicable only to particular filtration systems. For example, thepresently disclosed systems are applicable not only to air filtration,but also to any flowing gas or liquid. Moreover, the presently disclosedload sensors may be positioned not only downstream from a filter, butalternatively or additionally upstream from a filter, and/orperpendicularly to a fluid/gas flow. Moreover, the presently disclosedload sensors may be used in relation not only to deformable filtermedia, but also to rigid filter media, and to any shape of filter media.Moreover, the presently disclosed load sensors do not just trigger adirty filter alarm at a single predetermined load (e.g., akin to on/offswitch), but rather they enable a continuum or gradient of loads invarying atmospheric conditions, any of which may trigger different typesof alarms or actions, and which may be normalized to account for aparticular level and/or direction of air/fluid flow.

FIG. 1C is a schematic diagram of an exemplary air flow HVAC filtersystem and environment in which embodiments of the present disclosuremay be practiced. FIG. 1C depicts an air or gas environment 30,comprising a duct 32 having one or more filters 34, 36 and any type offluid/gas impeller, e.g., a fan, blower, or pump 38. It should beappreciated that the air or gas environment 30 may include one or moreupstream filters 34, one or more downstream filters 36, or both of oneor more upstream filters 34 and one or more downstream filters 36. Thus,while FIG. 1C depicts one or more load sensors 42 depicted in relationto a downstream filter 36, as will be described in more detail withrespect to the disclosure that follows, the air or gas environment 30may include one or more load sensors 42 at an upstream filter 34, or atboth an upstream filter 34 and a downstream filter 36. Thus, theparticular embodiment of FIG. 1C should not be construed as limitingwith respect to the arrangement of filters in relation to the duct 32and/or the fan, blower, or pump 38.

Nevertheless, as shown in FIG. 1C, filter 36 is depicted as beingdisposed across an air or gas flow through duct 32 and as beingsupported by one or more framing elements or members 33 of duct 32.Moreover, as shown in FIG. 1C, one or more load sensors 42 are depictedas being disposed between filter 36 and framing elements or members 33of duct 32. In one embodiment, at least one load sensor 42 is connectedto a framing element or member 33 of duct 32 and configured to detectand measure an amount or extent of force that filter 36 applies againstthe framing element or member 33 through the load sensor. In oneembodiment, the load sensor 42 may be configured to detect and measure aportion of the force imparted by filter 36, such as one half, or onequarter of the filter, in cases where an opposing half or quadrant offilter 36 is supported and measured by another load sensor.Alternatively, the load sensor 42 may be configured to detect andmeasure a substantial majority component, or even all of a forceimparted by a filter against a framing element or member 33 of duct 32.

As shown in FIG. 1C, fan, blower, or pump 38 may be disposed incommunication with, and indeed may be driven by, a variable speed drive,such as a variable frequency drive (VFD) 40. Moreover, the depictedsystem may include a controller 44, which may be disposed in wiredand/or wireless communication with the VFD 40, the load sensor(s) 42, athermostat 46, and a user interface device 48. It should be appreciatedthat the functionality of the controller 44, thermostat 46, and userinterface device 48 may be combined, and/or separated across each otherin any desired manner. For example, a single device may function as awireless controller of VFD 40 and wireless receiver of signals from loadsensor(s) 42, while performing thermostat logic and receiving userinputs.

FIG. 1D is a schematic diagram of an exemplary fluid flow filter system50 and environment in which embodiments of the present disclosure may bepracticed. In particular, FIG. 1D depicts an air exchanger comprising anair duct 52 and any type of fluid conduit 54. Again, it should beappreciated that the fluid filtration and fluid filters of the presentdisclosure are applicable to any fluid system, such as a waterfiltration system, an oil filtration system, a refrigerant filtrationsystem, a brake fluid filtration system, a coolant filtration system,and so on. Thus, while in one embodiment, fluid conduit 54 may carry arefrigerant or heating fluid, it should be appreciated that theembodiment of FIG. 1D is only exemplary in nature and should not beviewed as limiting of the scope of the present disclosure.

In one embodiment, the fluid filtration system of FIG. 1D includes afirst fluid filter 56 and a second fluid filter 58 disposed in line withfluid conduit 54, in which fluid is driven by a fan, pump, or otherimpeller 60. While first fluid filter 56 and second fluid filter 58 areboth depicted as being downstream from the fan, pump, or other impeller60, it should be appreciated that the fluid filters 56, 58 may bedisposed upstream, downstream, and/or upstream and downstream from thefan, pump, or other impeller 60. Like the VFD 40 and load sensor(s) 42of FIG. 1C, the fluid filtration system 50 of FIG. 1D may be disposed inwired and/or wireless communication with a controller 44, thermostat 46,and/or user input device 48. In particular, each filter 56, 58 mayinclude a load sensor disposed in relation to the filter such that it isconfigured to detect and measure an amount or extent of force impartedby the fluid filter 56, 58 on the fluid conduit 54 and/or on a conduitelement or member of fluid conduit 54.

The systems of FIGS. 1C and 1D will now be described with respect toexemplary embodiments of various suitable arrangements between a filterand a load sensor, for purposes of comparison to various thresholds andalarm limits within a variable flow environment. Specifically, FIGS.2A-2C, 3, 4A-4B, 5A-5D, and 6-8 will now depict and describe variousembodiments of an arrangement between a load sensor and a filter, any ofwhich may be applicable to the load sensor 42 and filters 34, 36, 56, 58described with respect to FIGS. 1C and 1D.

Referring now to FIGS. 2A, 2B, and 2C, a filter system 100 is shownhaving a housing 102 (e.g., a frame) that may support or otherwise bedisposed around a filter media 104. Filter system 100 may be applicableto any filtration system described with respect to FIGS. 1A, 1B, 1C,and/or 1D, such as any filter system used in, e.g., HVAC systems, amongother systems requiring air and/or fluid filtration. Filter media 104may be any suitable media configured to remove particulate matter from agas or fluid flow. In some embodiments, filter media 104 may be porousor have another suitable configuration. A mounting component 106 mayextend from a surface of housing 102. In the embodiment shown in FIGS.2A-2C, mounting component 106 may extend from a downstream portion ofhousing 102 anywhere around a perimeter of housing 102. A load sensor108 may be disposed between filter media 104 and mounting component 106.Alternatively, load sensor 108 may be disposed between a frame or memberof filter media 104 and a mounting component 106 and/or housing 102 of afiltrations system. As described above, load sensor 108 may be a loadcell, strain gauge, or any other suitable sensor for measuring an amountof compression force exerted by filter media 104 (or a frame or memberthereof) on mounting component 106 and/or housing 102. That is, asfilter media 104 collects particulate matter, it may clog and exert aforce in the direction of air/fluid/gas flow 110 that applies a force onand compresses, e.g., load sensor 108.

Load sensor 108 may communicate a signal to a receiver or other suitabledevice to indicate a loading condition of filter media 104. For example,as described herein, the receiver configured to receive a signal of loadsensor 108 may be a component of VFD 40, controller 44, thermostat 46,and/or user interface device 48. In some embodiments, load sensor 108may continuously send a signal to the receiver. In an alternativeembodiment, load sensor 108 may send a signal only if a measured forceexceeds a threshold force (e.g., indicating that the filter media 104should be changed). In some embodiments, load sensor 108 may send asignal only in response to a request made by the receiver. It should beappreciated that the load sensor 108 (e.g., a load cell) can beconnected through either a wired or wireless interface to transfer itssignal to electronics and thereby trigger an alarm or some indicationthat it is time to change the filter. A user, such as a contractorand/or homeowner, could configure the trigger point based on the type offilter media, flow rate, an elapsed time of the increased force (toprevent false triggers due to start up) and flow density, to name a few.

Again, it should be appreciated that in the case of the load sensor 108of system 100 (depicted in FIGS. 2A-2C, or in any other loadsensor—filter arrangements of FIGS. 3-8), the depicted load sensor maybe provided in communication with a variable speed drive and acontroller that is configured to perform a method of determining anamount or extent of loading or clogging of the depicted filter. Forexample, in one embodiment, the controller may be configured to receivea value of operation of a fan or blower of a variable speed filtration(e.g., HVAC or fluid) system. The value of operation of the fan orblower may include one or more of a fan setting, a pump setting, anintensity setting, a fan speed, a rotational velocity, a voltage, acurrent, an air flow rate, a force, or a windspeed. The controller maybe further configured to receive one or more real-time environmentalconditions including one or more of a temperature measurement, ahumidity measurement, an air or fluid density measurement, an altitudemeasurement, or an air or fluid pressure measurement of the filtrationsystem, and modify the determined threshold filter force based on thereceived one or more real-time environmental conditions. The controllermay further be configured to receive, from the load sensor, a value offorce of a filter of the filtration system against the load sensor oranother member of the filtration system. The controller may further beconfigured to compare the received value of force of the filter toeither the received value of operation of the fan or blower, or apredetermined value of force stored in relation to the value ofoperation of the fan or blower. Finally, the controller may beconfigured to determine whether to generate a signal associated with thefilter being more loaded, clogged, or dirty, than desired. In oneembodiment, the controller may generate a signal associated with thefilter being more loaded, clogged, or dirty, than desired, if thereceived value of force of the filter is outside a threshold value fromthe received value of operation of the fan or blower, or thepredetermined value of force stored in relation to the value ofoperation of the fan or blower.

FIG. 3 depicts a filter system 300 that is substantially similar tofilter system 100, except that filter system 300 may not necessarilyinclude a mounting component 106. Instead, filter system 300 may includea load sensor 308 (e.g., that is substantially similar to sensor 108described with reference to FIGS. 2A-2C), which may be disposed betweenfilter media 104 and a downstream surface (e.g., a flange or lip) ofhousing 102 to measure a force exerted by filter media 104 on loadsensor 308.

FIGS. 4A-4B depict a filter system 400 that is substantially similar tofilter system 100, except that a mounting component 406 may extend froman upstream surface (e.g., a flange or lip) of housing 102. A sensor 408(e.g., that is substantially similar to sensor 108) may be disposedbetween housing 102 and mounting component 408 to measure a tensileforce exerted by filter media 104 in the direction of airflow 110. Thatis, as filter media 104 collects particulate matter, it may clog andexert a force in the direction of airflow 110 and pull on sensor 408.

FIGS. 5A-5D depict a filter system 500 that is substantially similar tofilter system 400, except that filter system 500 may not necessarilyinclude a mounting component 406. Instead, filter system 500 may includea sensor 508 (e.g., that is substantially similar to sensor 108described with reference to FIGS. 2A-2C), which may be disposed betweenfilter media 104 and an upstream (e.g., top) surface of housing 102 tomeasure a force exerted by filter media 104 on sensor 508. As shown inFIG. 5B, sensor 508 may be disposed between an upstream bracket and thefilter media 104, and therefore configured to detect and measure tensioncaused by an increased clogging of, and reduced airflow through, thefilter media 104, and therefore increasing force in a downstreamdirection. As shown in FIG. 5D, in one embodiment, a sensor 508 may bedisposed in a channel bracket attached to the filter media 104, andtherefore configured to detect either tension or compression caused byan increased clogging of, and reduced airflow through, the filter media104, and therefore increasing force in a downstream direction.

FIG. 6 depicts a filter system 600 that is substantially similar tofilter system 100, except that filter system 600 may not include amounting component 106. Instead, filter system 600 may include a sensor608 (e.g., that is substantially similar to sensor 108 described withreference to FIGS. 2A-2C), which may be disposed between a side surfaceof housing 102 and a side surface of filter media 104 to measure a forceexerted by filter media 104 on sensor 608. Sensor 608 may measure theforce exerted by filter media 104 in multiple vectors (e.g., one or moreof a downward force and an inward radial force).

FIG. 7 depicts a filter system 700 that is substantially similar tofilter system 100, except that filter system 700 may include a mountingcomponent 706 that is coupled to one or more surfaces of housing 102(e.g., a longitudinal side surface and a lateral side surface). Sensor708 may be disposed between mounting component 706 and filter media 104to measure a force exerted by filter media 104 on sensor 708. Sensor 708may measure the force exerted by filter media 104 in multiple vectors(e.g., one or more of a tensile force, a compressive force, and aninward radial force).

FIG. 8 depicts a filter system 800 having a housing 802 and a filtermedia 804. Housing 802 may be disposed within a flow path such as, e.g.,a duct 801. In some embodiments, filter media 804 may be substantiallyconical or may be arranged in another suitable configuration. Theconfiguration of filter media 804 may cause airflow 110 to take anon-uniform path 812 through filter media 804. A sensor 808 (that issubstantially similar to sensor 108) may be disposed between filtermedia 804 and housing 802 at a location of housing 802 that complementsor corresponds to an airflow path, e.g., an airflow path that isopposite in direction of the largest airflow vector component.

Any of the systems described above with respect to FIGS. 1-8 may be usedto perform any of the methods disclosed herein. In particular, any ofthe systems described with respect to FIGS. 1-8 may be configured toperform the exemplary methods of FIGS. 9 and 10. FIG. 9 is a flowchartof an exemplary method 900 for generating a filter status notificationor signal in a variable flow filtration system, according to anexemplary embodiment of the present disclosure. As shown in FIG. 9,method 900 may include receiving an operating condition of a variablespeed impeller associated with a filtration system (step 902), receivingan environmental condition of the filtration system (step 904), anddetermining a threshold filter force associated with (i) the receivedoperating condition of the variable speed impeller associated with thefiltration system, and (ii) the received environmental condition of thefiltration system (step 906). Method 900 may further include receiving,from a load sensor, a real-time filter force imparted by a filter of thefiltration system on the load sensor and/or a component of thefiltration system, the force of the filter on the component beingimparted by a flow of gas or fluid driven by the variable speed impeller(step 908). Method 900 may further include comparing the receivedreal-time filter force to the determined threshold filter force (step910), and generating a filter status notification or signal based on thecomparison of the real-time filter force to the determined thresholdfilter force (step 912).

In one embodiment of method 900, the received operating condition may bereceived continuously in real-time, the one or more real-timeenvironmental conditions may be received continuously in real-time, andthe real-time filter force may be received from the load cellcontinuously in real-time. Alternatively, the received operatingcondition may be received at a first predetermined interval, the one ormore real-time environmental conditions may be received at a secondpredetermined interval, and the real-time filter force may be receivedfrom the load cell at a third predetermined interval, wherein the first,second, and third predetermined intervals are different from each otheror the same. In yet another exemplary embodiment, the real-time filterforce may be received from the load cell continuously in real-time,whereas the one or more received operating conditions may be received ata first predetermined interval (e.g., every second, every 30 seconds,every minute, every 15 minutes, etc.), and the one or more real-timeenvironmental conditions may be received at a second predeterminedinterval different from the first predetermined interval (e.g., adifferent one of every second, every 30 seconds, every minute, every 15minutes, etc.).

FIG. 10 is a flowchart of another exemplary method 1000 of generating afilter status notification or signal in a variable flow filtrationsystem, according to an exemplary embodiment of the present disclosure.In one embodiment, method 1000 may include receiving an operatingcondition a variable speed impeller of a filtration system (step 1002).For example, the operating condition may include one or more of a fansetting, a pump setting, an intensity setting, a fan speed, a rotationalvelocity, a voltage, a current, an air/fluid flow rate, and a forceassociated with the variable speed impeller of the filtration system.Method 1000 may further include determining a threshold filter forceassociated with the received operating condition (step 1004). Forexample, method 1000 may include determining an increased thresholdfilter force proportionally to increases in one or more of: the fansetting, the pump setting, the intensity setting, the fan speed, therotational velocity, the voltage, the current, the air/fluid flow rate,and the force associated with the variable speed impeller of thefiltration system (step 1004).

Method 1000 may further include receiving one or more real-timeenvironmental conditions of the filtration system (step 1006). Forexample, method 1000 may include receiving one or more of a temperaturemeasurement, a humidity measurement, an air or fluid densitymeasurement, an altitude measurement, or an air or fluid pressuremeasurement of the filtration system. Method 1000 may further includemodifying the determined threshold filter force based on the receivedone or more real-time environmental conditions (step 1008). For example,the determined threshold filter force may be modified so as (i) todecrease the determined threshold filter force proportionally toincreases in the temperature measurement and/or proportionally toincreases in the altitude measurement; and (ii) to increase thedetermined threshold filter force proportionally to increases in thehumidity measurement, to increases in the air or fluid densitymeasurement, and/or to increases in the air or fluid pressuremeasurement of the filtration system.

Method 1000 may further include receiving, from a load cell, a real-timefilter force imparted by a filter of the filtration system on the loadcell and/or a component of the filtration system, the force of thefilter on the component being imparted by a flow of gas or fluid drivenby the variable speed impeller (step 1010), comparing the receivedreal-time filter force to the modified determined threshold filter force(step 1012), and generating a filter status notification or signal basedon the comparison of the real-time filter force to the determinedthreshold filter force (step 1014).

Other embodiments of the disclosure will be apparent to those skilled inthe art from consideration of the specification and practice of theinvention disclosed herein. It is intended that the specification andexamples be considered as exemplary only, with a true scope and spiritof the invention being indicated by the following claims.

1-20. (canceled)
 21. A computer-implemented method, comprising:determining a threshold based on one or more first conditions of avariable speed first component of a filtration system and one or moresecond conditions; receiving, from a sensor, a force imparted by afilter of the filtration system on the sensor and/or a second componentof the filtration system, the force of the filter on the sensor and/orthe second component being imparted by a flow of air, gas, or fluiddriven by the variable speed first component; comparing the receivedforce to the determined threshold ; and generating a notification orsignal based on the comparison of the force to the determined threshold.22. The computer-implemented method of claim 21, wherein the one or morefirst conditions include one or more of a fan setting, a pump setting,an intensity setting, a fan speed, a rotational velocity, a voltage, acurrent, an air/fluid flow rate, or a force.
 23. Thecomputer-implemented method of claim 21, wherein the one or more secondconditions include one or more of a temperature measurement, a humiditymeasurement, an air or fluid density measurement, an altitudemeasurement, or an air or fluid pressure measurement of the filtrationsystem.
 24. The computer-implemented method of claim 21, wherein atleast one of the one or more first conditions, the one or more secondconditions, or the force, is received continuously in real-time.
 25. Thecomputer-implemented method of claim 21, wherein determining a thresholdincludes modifying an initially determined threshold based on changes inthe one or more second conditions.
 26. A control system for a variableflow filtration system, the control system comprising: a digital datastorage device storing instructions for generating a notification orsignal; and a processor configured to execute the stored instructions toperform a method comprising: determining a threshold based on a firstcondition of a variable speed first component of the variable flowfiltration system and one or more second conditions; receiving, from asensor, a force imparted by a filter of the variable flow filtrationsystem on the sensor or on a second component of the variable flowfiltration system, the force of the filter being imparted by a flow ofair, gas, or fluid moved by the variable speed the first component;comparing the received force to the determined threshold ; andgenerating the notification or signal based on the comparison of theforce to the determined threshold.
 27. The control system of claim 26,wherein the first condition includes one or more of a fan setting, apump setting, an intensity setting, a fan speed, a rotational velocity,a voltage, a current, an air/fluid flow rate, or a force associated withthe variable speed first component of the variable flow filtrationsystem.
 28. The control system of claim 26, wherein the one or moresecond conditions includes one or more of a temperature measurement, ahumidity measurement, an air or fluid density measurement, an altitudemeasurement, or an air or fluid pressure measurement of the variableflow filtration system.
 29. The control system of claim 26, wherein thesensor is mounted at surface of the filter facing upstream, facingdownstream, and/or facing perpendicular to the flow of gas or fluid. 30.The control system of claim 26, wherein the sensor is configured tomeasure a compressive or tensile force exerted by the filter.
 31. Thecontrol system of claim 26, wherein determining a threshold includesmodifying an initially determined threshold based on changes in the oneor more second conditions.
 32. A variable flow filtration system,comprising: a filter disposed across a flow of fluid or gas; a variablespeed first component configured to move air, fluid, or gas through thefilter; a sensor disposed adjacent to the filter and/or a secondcomponent of the variable flow filtration system; and a controllerconfigured to: determine a threshold associated with one or more firstconditions of the variable speed first component and one or more secondconditions; receive, from the sensor, a force imparted by the filter ofthe variable flow filtration system on the sensor or the secondcomponent of the variable flow filtration system; compare the receivedforce to the determined threshold ; and generate a notification orsignal based on the comparison of the force to the determined threshold.33. The variable flow filtration system of claim 32, wherein the one ormore first conditions includes one or more of a fan setting, a pumpsetting, an intensity setting, a fan speed, a rotational velocity, avoltage, a current, an air/fluid flow rate, or a force associated withthe variable speed first component of the variable flow filtrationsystem.
 34. The variable flow filtration system of claim 32, wherein theone or more second conditions includes one or more of a temperaturemeasurement, a humidity measurement, an air or fluid densitymeasurement, an altitude measurement, or an air or fluid pressuremeasurement of the variable flow filtration system.
 35. The variableflow filtration system of claim 32, wherein determining the thresholdincludes modifying an initially determined threshold based on changes inthe one or more second conditions.
 36. The variable flow filtrationsystem of claim 32, wherein the filter is located upstream or downstreamof the variable speed first component.
 37. The variable flow filtrationsystem of claim 32, wherein the controller is further configured to:receive the one or more first conditions at a first interval; receivethe one or more second conditions at a second interval; and receive theforce from the sensor at a third interval, wherein the first, second,and third intervals are different from each other or the same.
 38. Thevariable flow filtration system of claim 32, wherein the sensor isconfigured to measure a compressive or tensile force exerted by thefilter.
 39. The variable flow filtration system of claim 32, wherein thevariable speed first component moves fluid or gas through the filter ina non-uniform path.
 40. The variable flow filtration system of claim 32,wherein the sensor is mounted at surface of the filter facing upstream,facing downstream, and/or perpendicular to the movement of air, gas, orfluid.